LED tube lamp with improved compatibility with an electrical ballast

A light emitting diode (LED) tube lamp, comprising:

• a lamp tube;
• a first external connection terminal and a second external connection terminal coupled to the lamp tube and for receiving an external driving signal;
• a first rectifying circuit coupled to the first external connection terminal and the second external connection terminal and configured to rectify the external driving signal to produce a rectified signal;
• a filtering circuit coupled to the first rectifying circuit and configured to filter the rectified signal to produce a filtered signal;
• an LED lighting module coupled to the filtering circuit and configured to receive the filtered signal for emitting light;
• and
• a ballast interface circuit coupled to the first rectifying circuit,
• wherein the ballast interface circuit is configured such that when the external driving signal is initially input at the first external connection terminal and second external connection terminal, the ballast interface circuit will initially be in an open-circuit state, which prevents the LED tube lamp from emitting light, until the ballast interface circuit enters a conduction state, which conduction state allows a current input at the first external connection terminal/second external connection terminal to flow through the LED lighting module and thereby allows the LED tube lamp to emit light,
• wherein the ballast interface circuit comprises a first electronic switch and a second electronic switch;
• the first electronic switch has a terminal coupled to the second electronic switch;
• wherein the ballast interface circuit is configured such that when the external driving signal is initially input at the first external connection terminal and second external connection terminal, the second electronic switch will be in an open-circuit state, and then the external driving signal passes through a diode or the first rectifying circuit to produce a DC signal, with the open-circuit state continuing until the DC signal reaches an amplitude causing the first electronic switch to enter a conducting state to an extent that in turn triggers the second electronic switch into a conducting state, making the ballast interface circuit enter the conduction state, and
• wherein the DC signal is produced after the external driving signal passes through the diode or the first rectifying circuit and then through a voltage division circuit.

A light emitting diode (LED) tube lamp, comprising:

• a lamp tube;
• a first external connection terminal and a second external connection terminal coupled to the lamp tube and for receiving an external driving signal;
• a first rectifying circuit coupled to the first external connection terminal and the second external connection terminal and configured to rectify the external driving signal to produce a rectified signal;
• a filtering circuit coupled to the first rectifying circuit and configured to filter the rectified signal to produce a filtered signal;
• an LED lighting module coupled to the filtering circuit and configured to receive the filtered signal for emitting light;
• and
• a ballast interface circuit coupled to the first rectifying circuit,
• wherein the ballast interface circuit is configured such that when the external driving signal is initially input at the first external connection terminal and second external connection terminal, the ballast interface circuit will initially be in an open-circuit state, which prevents the LED tube lamp from emitting light, until the ballast interface circuit enters a conduction state, which conduction state allows a current input at the first external connection terminal/second external connection terminal to flow through the LED lighting module and thereby allows the LED tube lamp to emit light,
• wherein:
• the first rectifying circuit comprises a rectifying unit and a terminal adapter circuit, and the rectifying unit is coupled to the terminal adapter circuit and is configured to perform half-wave rectification, and the terminal adapter circuit is configured to transmit the external driving signal received via at least one of the first external connection terminal and the second external connection terminal;
• the ballast interface circuit is coupled between the rectifying unit and the terminal adapter circuit;
• and
• the rectifying unit comprises two diodes, one of which has an anode connected to a cathode of the other diode, which connection forms a half-wave node, and the ballast interface circuit is coupled to the half-wave node.